Three British men have been sentenced to jail and caning for sexually assaulting a Malaysian woman during a stag party in Singapore.

The defendants – Khong Tam Thanh, 22, Michael Le, 24, and Vu Thai Son, 24 – were originally accused of taking turns to rape the woman in a hotel room. The three pleaded guilty to a reduced charge of aggravated outrage of modesty.

At the end of the four-day trial, high court judge Hoo Sheau Peng lambasted their “reprehensible” conduct and sentenced them to jail terms of between five and a half and six and a half years.

They were also sentenced to between five and eight strokes of a 1.2-metre rattan cane, a punishment dating to British colonial rule.

“While she was asleep and quite unable to protect herself, they took advantage of her vulnerable state so as to commit these serious sexual crimes,” the judge said. “In doing so, they showed no respect for her dignity and autonomy, and no regard for any harm and hurt they might cause to her.”

The attack took place last September when the three were in the city-state for a stag party. The groom, the brother of Thanh, was also on the trip but was not involved in the incident.

The men met the 23-year-old woman at a nightclub, and she went back to the Carlton hotel with one of their friends – who was not arrested – where they had sex.

Later, Thanh, Son, and Le took turns to enter the room and have sex with her without her consent, the court heard. Khong left the hotel room door ajar after he had assaulted her, according to the Straits Times, which the judge said facilitated further sexual offences.

The woman woke up as Le assaulted her and confronted him. She filed a police report that day.

​Thanh and Son, who worked as beauticians in Britain, were also convicted of an additional charge of sexual assault.

Deputy public prosecutor Gnanasihamani Kannan said the three men “objectified her, they treated her like a thing to be used and abused”.

The women did not have to testify in court as the defendants pleaded guilty after the prosecution amended the charges, according to the Straits Times.

Rights groups have condemned the caning of prisoners in Singapore, a country known for its zero tolerance towards crime. Vandalism, overstaying of visas, robbery, drug abuse and sexual abuse are offences for which caning can be used in a sentence.

Prisoners are stripped to expose their buttocks and strapped to a wooden trestle. The pain has been described as excruciating, and a medical officer is on duty as the practice often breaks the skin.

In 2016, authorities carried out close to 1,000 caning sentences, with about a third of those caned being foreigners, according to a US Department of State rights report.